You won't believe the tricks your mind is playing. Illusions are a part of the human mind and are known to distort our senses. Any of our senses can get distorted in the process. Illusions with our eyes are known as optical illusions, and illusions with our ear are known as auditory illusions.
Below are some images which would clear the concept of illusions for you even further.
Have a look at them and see how your brain performs!